Program Flow Analysis for Reducing and Estimating the Cost of Test Coverage Criteria

Testing a software system consists of executing it over a suitable sample of input data and then checking if the output produced matches what was expected. Testing is widely used to enhance software quality, and, specifically, to uncover bugs that are inevitably introduced during the software development process. One of the most difficult problems in testing is knowing when to stop the testing process. On the one hand, it is not possible in general to give an answer to whether a test suite guarantees the absence of faults. On the other hand, we need a way to limit the cost of testing. Therefore, it is useful to have criteria to determine when a program has been tested enough. Ideally, the testing process should be planned in advance. However, in practice the tests are incorporated little by little, until some adequacy criterion is satisfied. In particular, different coverages can be used to determine when the program has been tested enough. The idea is to guarantee that each statement, decision or other feature of the program has been executed at least once under some test. A major problem is that testing takes a considerable amount of the time and resources spent on producing software [?]. Therefore, it would be useful to have ways 1. to reduce the cost of testing, and 2. to estimate this cost. In particular, the number of tests to be executed impacts heavily on the cost of testing. In fact, the time and resources needed for testing increase as the number of test cases increases. Hence, to reduce the cost of testing, the number of test cases generated to satisfy a selected test criterion should be as small as possible. Moreover, a bound on the number of tests that have to be performed to satisfy a selected test strategy can be used by managers and testers to estimate the effort needed to carry out the tests.Sociedad Argentina de Informática e Investigación Operativ

HIV treatment as prevention : models, data, and questions-towards evidence-based decision-making

Antiretroviral therapy (ART) for those infected with HIV can prevent onward transmission of infection, but biological efficacy alone is not enough to guide policy decisions about the role of ART in reducing HIV incidence. Epidemiology, economics, demography, statistics, biology, and mathematical modelling will be central in framing key decisions in the optimal use of ART. PLoS Medicine, with the HIV Modelling Consortium, has commissioned a set of articles that examine different aspects of HIV treatment as prevention with a forward-looking research agenda. Interlocking themes across these articles are discussed in this introduction. We hope that this article, and others in the collection, will provide a foundation upon which greater collaborations between disciplines will be formed, and will afford deeper insights into the key factors involved, to help strengthen the support for evidence-based decision-making in HIV prevention

Utility rebates for ENERGY STAR appliances: Are they effective?

We estimate the impact of utility cash rebates on the market share of ENERGY STAR appliances by exploiting the variation in timing and size of rebates across US states. We find that a dollar increase in the population-weighted utility rebate raises the share of ENERGY STAR qualified clothes washers by 0.4%, but does not affect dishwasher and refrigerator shares. Using information on energy saved by an ENERGY STAR appliance and assuming a redemption rate of 40%, the cost per tonne of carbon saved is about $140 for the clothes washers rebate program. The corresponding cost of a megawatt hour saved, about$28, is lower than the estimated cost of building and operating an additional power plant and the average on-peak spot price. We conclude that the ENERGY STAR clothes washers rebate program is, on average, a cost-effective way for utilities to reduce electricity demand

Estimating the cost-effectiveness of detecting cases of chronic hepatitis C infection on reception into prison

Background In England and Wales where less than 1% of the population are Injecting drug users (IDUs), 97% of HCV reports are attributed to injecting drug use. As over 60% of the IDU population will have been imprisoned by the age of 30 years, prison may provide a good location in which to offer HCV screening and treatment. The aim of this work is to examine the cost effectiveness of a number of alternative HCV case-finding strategies on prison reception Methods A decision analysis model embedded in a model of the flow of IDUs through prison was used to estimate the cost effectiveness of a number of alternative case-finding strategies. The model estimates the average cost of identifying a new case of HCV from the perspective of the health care provider and how these estimates may evolve over time. Results The results suggest that administering verbal screening for a past positive HCV test and for ever having engaged in illicit drug use prior to the administering of ELISA and PCR tests can have a significant impact on the cost effectiveness of HCV case-finding strategies on prison reception; the discounted cost in 2017 being £2,102 per new HCV case detected compared to £3,107 when no verbal screening is employed. Conclusion The work here demonstrates the importance of targeting those individuals that have ever engaged in illicit drug use for HCV testing in prisons, these individuals can then be targeted for future intervention measures such as treatment or monitored to prevent future transmission

The Effects of State Policy Design Features on Take Up and Crowd Out Rates for the State Children’s Health Insurance Program

We evaluate the effects of state policy design features on SCHIP take up rates and on the degree to which SCHIP benefits crowd out private benefits. The results indicate that overall program take up rates range from 10.1 to 10.5 percent. However, there is considerable heterogeneity across states, suggesting a potential role of inter-state variation in policy design. We find that several design mechanisms have significant and substantial positive effects on take up. For example, eliminating asset tests, offering continuous coverage, simplifying the application and renewal processes, and extending benefits to parents all have sizable and positive effects on take-up rates. Mandatory waiting periods, on the other hand, consistently reduce take-up rates. In all, inter-state differences in outreach and anti-crowd out efforts explain roughly one quarter of the cross-state variation in take-up rates. Concerning the crowding out of private health insurance benefits, we find that between one quarter and one third of the increase in public health insurance coverage for SCHIP eligible children is offset by a decline in private health coverage. We find little evidence that the policy-induced variation in take-up is associated with a significant degree of crowd-out, and no evidence that the negative effect on private coverage caused by state policy choices is any greater than the overall crowding out effect. This suggests that states are not augmenting take-up rates by enrolling children that are relatively more likely to have private health insurance benefits.State Children’s Health Insurance Program (SCHIP), Crowd Out, Take Up

Human resources needs for universal access to antiretroviral therapy in South Africa: a time and motion study

<p>Background - Although access to life-saving treatment for patients infected with HIV in South Africa has improved substantially since 2004, treating all eligible patients (universal access) remains elusive. As the prices of antiretroviral drugs have dropped over the past years, availability of human resources may now be the most important barrier to achieving universal access to HIV treatment in Africa. We quantify the number of HIV health workers (HHWs) required to be added to the current HIV workforce to achieve universal access to HIV treatment in South Africa, under different eligibility criteria.</p> <p>Methods - We performed a time and motion study in three HIV clinics in a rural, primary care-based HIV treatment program in KwaZulu-Natal, South Africa, to estimate the average time per patient visit for doctors, nurses, and counselors. We estimated the additional number of HHWs needed to achieve universal access to HIV treatment within one year.</p> <p>Results - For universal access to HIV treatment for all patients with a CD4 cell count of ≤350 cells/μl, an additional 2,200 nurses, 3,800 counselors, and 300 doctors would be required, at additional annual salary cost of 929 million South African rand (ZAR), equivalent to US$141 million. For universal treatment (‘treatment as prevention’), an additional 6,000 nurses, 11,000 counselors, and 800 doctors would be required, at an additional annual salary cost of ZAR 2.6 billion (US$ 400 million).</p> <p>Conclusions - Universal access to HIV treatment for patients with a CD4 cell count of ≤350 cells/μl in South Africa may be affordable, but the number of HHWs available for HIV treatment will need to be substantially increased. Treatment as prevention strategies will require considerable additional financial and human resources commitments.</p&gt

An ant colony optimization approach for maximizing the lifetime of heterogeneous wireless sensor networks

Maximizing the lifetime of wireless sensor networks (WSNs) is a challenging problem. Although some methods exist to address the problem in homogeneous WSNs, research on this problem in heterogeneous WSNs have progressed at a slow pace. Inspired by the promising performance of ant colony optimization (ACO) to solve combinatorial problems, this paper proposes an ACO-based approach that can maximize the lifetime of heterogeneous WSNs. The methodology is based on finding the maximum number of disjoint connected covers that satisfy both sensing coverage and network connectivity. A construction graph is designed with each vertex denoting the assignment of a device in a subset. Based on pheromone and heuristic information, the ants seek an optimal path on the construction graph to maximize the number of connected covers. The pheromone serves as a metaphor for the search experiences in building connected covers. The heuristic information is used to reflect the desirability of device assignments. A local search procedure is designed to further improve the search efficiency. The proposed approach has been applied to a variety of heterogeneous WSNs. The results show that the approach is effective and efficient in finding high-quality solutions for maximizing the lifetime of heterogeneous WSNs

Value at Risk models with long memory features and their economic performance

We study alternative dynamics for Value at Risk (VaR) that incorporate a slow moving component and information on recent aggregate returns in established quantile (auto) regression models. These models are compared on their economic performance, and also on metrics of first-order importance such as violation ratios. By better economic performance, we mean that changes in the VaR forecasts should have a lower variance to reduce transaction costs and should lead to lower exceedance sizes without raising the average level of the VaR. We find that, in combination with a targeted estimation strategy, our proposed models lead to improved performance in both statistical and economic terms

Achieving economic and environmental sustainability through optimum balance of costs

Awareness and significance of sustainable development (SD) has been growing around the world for the last few decades. Sustainable construction is now considered a way for the construction industry to contribute to this larger effort. It is clear why the construction industry must respond accordingly and focus its attention on developing more sustainable buildings - not least because of its huge size, the vast amount of resources it consumes and its major impact on the built and natural environments. This research work therefore aims to examine the concept of sustainability, investigate the costs related to producing sustainable buildings and the relationship that exists between these costs. A review of the literature showed that the concept of sustainability is broad but the economic, social and environmental aspects, which are inextricably linked, remain the three fundamental pillars of sustainability. Initial construction cost (IC), cost-in-use (CIU) and carbon cost (CC) were revealed as monetary means of appraising economic and environmental criteria. According to the review, social criteria are drivers: subjective and human factors, which affect the other two factors, directly or indirectly. It is concluded that inverse relationship often exists between IC and CIU but the movement of CC in relation to this is still unknown, being a new concept. Further stage of the research work will explore this grey area and consequently model through quantitative analysis the relationship that exists between IC, CIU and CC